Hoary Vervain

Verbena stricta

Hoary Vervain (Verbena stricta), also called Woolly Verbena, is a native perennial of the vervain family with stiff, gray-green, fuzzy stems that end in long, pencil-thin spikes. A ring of small purple flowers climbs each spike from June into September, and in the Black Hills it grows on dry, open ground around the foothills, in lower canyons and in open parks.

Free photos from other sources

Hoary Vervain: Ring of blue-violet flowers partway up a hairy spike — Hoary Vervain (Verbena stricta). Jim Pisarowicz, Public Domain. Get it at the source

Hoary Vervain: Upright plant with several purple flower spikes in prairie grass — Woolly Verbena. NPS Photo (Wind Cave National Park; photographer not named), Public Domain. Get it at the source

Hoary Vervain: Woolly gray-green leaves below spikes with rings of purple flowers — Woolly Verbena 2016-07-12 281. Chris Light, CC BY-SA 4.0, resized. Get it at the source

Hoary Vervain: Several tall plants with purple spikes in front of a pale eroded butte — Hoary Vervain (Verbena stricta). NPS Staff (U.S. National Park Service), Public Domain. Get it at the source

Hoary Vervain: Dense stand of plants with many purple flower spikes — Hoary Vervain (Verbena stricta) on Mixed Grass Prairie of Lacreek NWR. USFWS Mountain-Prairie (Photo: Tom Koerner/USFWS), CC BY 2.0, resized. Get it at the source

Hoary Vervain: A dry brown fruiting spike beside a flowering plant — Verbena stricta - Hoary Vervain 04. Jasper Shide, CC0 1.0. Get it at the source

Quick facts
Family	Verbenaceae · Vervain
Status	Native perennial
Blooms	June into September, peaking in July and August
Height	20–120 cm (8–47 in)
Where	Dry, open prairie, pastures, roadsides and disturbed ground in the foothills and open parks
Also called	Woolly Verbena, Woolly Vervain, Hoary Verbena, Tall Vervain, Hairy Verbena, tȟopȟéstola (Lakota), tȟó pȟestóla (Lakota)
Synonym	Verbena rigens, Verbena mollis, Verbena cuneifolia
Traditional use	Sitting Bull College's 1998 Culturally Important Plants of the Lakota says the Lakota drank a tea of the leaves and roots for fever and stomachaches. Gilmore (1913) recorded that the Dakota drank a leaf tea for stomachache and the Omaha made a hot, tea-like drink from the leaves.

Roots, seeds & germination

Root: Kansas Wildflowers says the roots can reach about 3.7 m (12 ft) deep, which helps the plant survive drought. Plants are short-lived, usually three or four years, but reseed readily.

Seed: Each flower makes four small, grayish-brown, finely bumpy nutlets 2.5–3 mm (about ⅛ in) long, held in the hairy calyx, with no fluff for the wind. The spikes are ready to collect when the fruit turns brown. Songbirds, prairie chickens and small mammals eat the seeds.

Germination: The seed needs a cold, moist period before it sprouts. SDSU recommends 60 days of cold-moist treatment before spring planting, or sowing outdoors in fall. It does best on open ground and tends to fade out of thick prairie plantings.

How do you identify Hoary Vervain?

Look for stiff, pencil-thin spikes up to about 30 cm (12 in) long with a ring of small purple to blue-violet flowers, about 8–9 mm (⅓ in) across, that moves up the spike: buds above, open flowers in the middle and green to brown fruit below. The leaves are opposite, nearly stalkless, oval to almost round, coarsely toothed and soft-fuzzy on both sides, which gives the plant its gray-green, hoary look. Blue Vervain grows in wet places and has many slender, candelabra-like spikes and narrow, lance-shaped leaves that aren't woolly. Bracted Vervain is a low, sprawling mat with tiny flowers hidden among leafy bracts. Dry brown spikes stand into winter.

When does it bloom?

June into September, peaking in July and August.

Where does it grow?

Dry, open, sunny ground with loamy, sandy or gravelly soil: mixed-grass prairie, pastures, roadsides, old fields and other disturbed ground. Cattle avoid its bitter leaves, so it increases with heavy grazing. In the Black Hills it grows around the foothills and in lower canyons and open parks. The 1986 Jewel Cave survey lists it as Woolly Verbena, National Park Service lists record it at Wind Cave and Mount Rushmore, and herbarium specimens come from all seven Black Hills counties, including Custer State Park.